While wounds heal more effectively in moist environments, bacterial infection poses increased risk. Use of antibiotics to treat bacterial infections can build bacterial resistance. Silver compounds are known to impart antimicrobial effects to a surface with minimal risk of developing bacterial resistance. Silver is delivered to the surface by sustained release of silver ions from the surface when in contact with moist environments, such as a wound bed.
Silver compositions, such as silver nitrate and silver sulfadiazine, are effective antimicrobials used in a variety of applications. However, they are typically not light stable, leave a stain on skin with which they come into contact, and in the case of silver nitrate, can be quickly depleted in an aqueous environment. Use of silver salts as antimicrobials have included the use of stabilizing agents to increase light stability such as those described in U.S. Pat. No. 2,791,518 (Stokes et al.) (using a first solution of ammonia, silver nitrate and barium nitrate; and a second solution of sodium chloride and sodium sulfate); and in U.S. Pat. No. 6,669,981 (Parsons et al.) (a silver salt in water/organic solvent followed by one or more stabilizing agents (e.g., ammonium salts, thiosulphates, chlorides and/or peroxides)).